1. Field of the Invention
The present invention relates to a technique for recognizing a touch operation.
2. Description of the Related Art
A touch input device has spread in these years. The touch input device imports the X and Y coordinate values of a touched position as input values in response to a touch on the screen by the user's finger or a stylus so as to perform various processes based on the input values. A technique for a so-called multi-touch in which the user operates the device by touching a plurality of points on the screen has been developing. The user can perform various operations such as enlargement, reduction, and scroll, for example, by touching two points with the user's right hand index figure and thumb in the multi-touch operation.
Designing as much of the whole device as possible on the screen is often required for such touch input devices. However, the user may happen to unconsciously touch the screen, for example, in order to hold the touch input device with the use's hand. When, as described above, the user mistakenly touches the screen on the touch input device in which a multi-touch operation can be performed, more touch inputs are recognized than the user intended. This can cause malfunction.
Japanese Patent Application Laid-Open No. 2009-217814 discloses that a touch on the peripheral edge of the touch panel is selectively ignored. In that case, when a touch on the edge moves a distance exceeding a predetermined distance or moves at a speed exceeding a predetermined speed, or when a touch started in the central region of the touch panel enters the edge, the touch on the edge is recognized as a part of a gesture.
However, various displays including a user interface are displayed even on the edge of a touch panel in many touch input devices in order to efficiently use the display region of the touch panel. A method disclosed in Japanese Patent Application Laid-Open No. 2009-217814 in which all touch points without moving are determined as invalid on the edge limits the contents allowed to be displayed on the edge.